Anyone remove/replace prop strut on H36C?

[tmjb]

Finally thought I was near to seeing the light re launching my new to me '81 H36C and then I noticed water from the bilge dripping from one of the two screws that bolt the strut to the hull.

The screws are slotted, countersunk bronze machine screws with a head diameter of about 11/16". I can't reach the nuts (doubled) to check their size and that is part of my problem. (anyone know the size?) Access to the forward one is supposedly through a circular hole in the fiberglass liner just aft of the stuffing box. However the hole is just too small to get my hand though with a reasonable chance of getting it back - and no way to work in there. The other is just aft of the edge of the fiberglass liner below the hatch in the aft locker that gives access (sort of) to the radial wheel on the rudder post. However, this is next to impossible to reach also.

I am thinking of cutting the liner where the previously mentioned access hole is to create a slot of about the same width as the hole that enables me to get my hand in and to reach the aft nuts through. I'm assuming that there is little structural significance to the liner in this area(?).

I've read about people removing/replacing struts to enable propshaft removal without removing their rudders. However I am not sure if any of them were H36C's.

I'm also wondering what my chances are of fixing this leak by removing the bolt, cleaning the hole, filling wiht 4200 and replacing, i.e without removing and replacing the hole strut. Any thoughts?

I'd much appreciate any insight.

Thanks in advance.

 

[rardiH36]

I posted a detailed description about one year ago. Do a search for strut specifying my user name rardiH36 and you should find it.

 

[tmjb]

Thanks so much. Found it through a Google search.

Once again you save the day. 3/8" bolts. Very helpful. Now I need to cut the access hole. Approximately what width did you make it? Looks wider than the original circular hole that mine has and I assume yours had.

Also, do you agree that if I remove and reinstall the original leaking bolt with new 4200 that should work?

I'm really anxious to get done and get her in the water before I lose too much of our season here.

 

[Ed Schenck]

My H37C strut access was no problem. And I did as you are contemplating, rebed the strut. I used new stainless bolts, put 4200 under the strut plate and in the holes, and tightened her down. Had someone hold screwdriver outside while I wrenched the locknut on top of a large stainless fender washer. That was fifteen years ago.

 

[tmjb]

Thanks Ed. You had leaks into the bilge via the bolts too?

 

[rardiH36]

Hi tmbj:

I'm back to my real computer now. My previous response was my made on my mobile phone and while taking a break on the tennis court.

Just some further answers and observations for your situation. And to get the "what's really going on" brain cells engaged -- (For me! as well as you):

- You say water from the bilge is dripping through. The area where the strut bolts are is considerably above the bilge on our Cherubini H36's. What water is in there?

- Regarding the size of the cut-out in the liner that needs to be made: I didn't measure when I did it. Cutting out some from that section of the interior liner isn't critical to the strength integrity of the hull. But from the picture I posted, look at the exhaust tube. Maybe you can extrapolate from there? Just make it large enough to get your hands and the socket wrench with extender fittings in easily. My cutting method was to drill holes in the corners of my area. Then just a hand held jig saw with a coarse tooth metal blade will cut just fine.

- I certainly understand your desire to finally get the boat in the water and go sailing. However, if one bolt is leaking, then the other might not be far behind? After you do the liner cut and then have unfettered access to the area: Fix the leaky one. Then punch out the other one and re-caulk as well.

- 4200: I have read that 4200 is a less aggressive 5200. So 4200 looks to be a fine choice. Ed Schenck recounted his good success. But if you don't have it already in your inventory, but instead have some other good quality caulk that is OK for underwater, then use that. A well secured nut/bolt combination, adequately torqued, provides the strength of the joint. Not the caulk. The caulk just seals the voids.

- Looking at your pdf pictures, your strut still looks a healthy yellow bronze. But if on your own close inspection you see any areas turning pink, then might as well bite the bullet and get a new strut. My post gives info about the source I found. If you are in a freeze area and need to haul the boat anyway every season, then maybe you could put this off for another year.

 

[rardiH36]

One more consideration about the size of the liner cut-out:

Keep in mind that the handle of the socket wrench will extend outside the vertical plane of the liner. The cut-out needs to be wide enough so you can "torque" the handle through a few degrees of rotation. That is why the cut-out that I made on my boat (see my picture) is bigger than what otherwise would be necessary for just being able to get a socket over the nut.

 

[tmjb]

One more consideration about the size of the liner cut-out:

Keep in mind that the handle of the socket wrench will extend outside the vertical plane of the liner. The cut-out needs to be wide enough so you can "torque" the handle through a few degrees of rotation. That is why the cut-out that I made on my boat (see my picture) is bigger than what otherwise would be necessary for just being able to get a socket over the nut.

Understood re the moile response. Thanks for the follow up.

The water was from washing the cockpit with a hose. Not much of it - although I have to further investigate the source to see if it will be problematic for normal use. The boat is stored in the boatyard - has been for years - inclined down to the stern. I had not realize until this that some water ponds here as a result.

Thanks for the tip re the size and method of the cut out. Hopefully I can figure that out and cut once. Good idea re the drilled holes in the corners.

I think you're right re the condition of the strut but I'll take anoter look now that i know what to look for. Great that you found a source for the original (ish) part.

Thanks again.

 

[Ed Schenck]

Did not have bilge water, higher than the bilge like yours. But drained hot water heater there when winterizing. And like yours the water pools there. Lucky to find it before the spring splash those many years ago.

 

[tmjb]

Thanks Ed. Yes, lucky for me too.

 

[tmjb]

Thanks to RardiH36 and Ed I cut a hole similar to RardiH36's and accessed the offending bolt last night and it was obvious why it was leaking - it was loose when I grabbed the threaded end of the screw!

I'm guessing that my wire brushing (preparatory to painting) of the strut loosened some old sealant - maybe the putty I read about somewhere - and that's what did it.

I was surprised to see that the screws only have standard washers and lock washers on the inside - no fender washer or backing plate.

Anyway I am, as always, indebted to this site and those that provide the invaluable input.